import java.util.Scanner;

public class main {
    public static void main(String[] args) {
        //判定一个数字是否是素数
        Scanner scanner = new Scanner(System.in);
        int sushu = scanner.nextInt();
        int flag = 0;
        for(int i = 2;i <= sushu / 2;i++)
        {
            if(sushu % i == 0)
            {
                flag = 1;
                break;
            }
        }
        if(flag == 0 || sushu == 1 || sushu == 2)
            System.out.println(sushu + "是素数");
        else
            System.out.println(sushu + "不是素数");
    }
}